Where they belong and where they do not
Speed humps work on private roads and car parks where vehicles are travelling faster than the environment can tolerate: near a pedestrian crossing point, on a long straight run that invites acceleration, at a blind corner, or approaching a loading area.
They work badly when scattered without thought. Too many humps and drivers accelerate between them, which is worse than no humps at all. Too close to a corner and vehicles take them at an angle, which is uncomfortable and hard on suspension. And on a route used by ambulances, buses or trucks, humps have real consequences that are worth thinking about before installing them.
On a public road, speed humps are a traffic engineering matter for the road authority, not something a property owner installs. Everything on this page concerns private roads, car parks and internal estate roads.
Types
Rubber modular humps are supplied in sections and bolted to the surface. They install quickly, come with yellow reflective inserts already in them, and can be removed or relocated if the layout changes. They are the usual choice for car parks and private roads. End caps matter, since an unfinished end is a trip hazard and catches wheels.
Asphalt humps are formed in place from hot mix. They look permanent because they are, they suit a road being built or resurfaced anyway, and they are cheaper across a wide roadway than modular sections. They cannot be relocated and they need marking applied on top, which then needs maintaining.
Speed cushions are narrower units placed in pairs across a lane so that wide-axle vehicles such as buses and emergency vehicles straddle them while cars do not. Worth considering on a route with bus or emergency access.
Profile matters too. A short sharp hump slows vehicles more aggressively but is uncomfortable and hard on vehicles. A longer flatter profile achieves a similar speed reduction more gently. The right choice depends on the target speed.
Marking and signage
This is the part that gets skipped and should not be.
A speed hump needs to be visible in time for a driver to slow down. That normally means chevron or hatched marking on the approach and on the hump itself, plus vertical signage warning of it, and reflective elements for night visibility. A black rubber hump on black asphalt in low light is close to invisible.
Marking also needs maintaining. Chevrons on a hump take direct tyre contact repeatedly, so they wear faster than surrounding lines. Thermoplastic on the hump markings is often worth the extra for this reason.
Practical considerations
- Drainage. A hump across a roadway is a dam. Water needs somewhere to go, or you get ponding on one side and a slippery surface. Modular units usually have channels for this and they need to be positioned so they work.
- Fixing. Bolted into asphalt or concrete with anchors. Loose bolts are a serious hazard, so fixings need checking periodically rather than installing and forgetting.
- Access. Consider ambulances, fire appliances, delivery trucks and rubbish collection. Speed cushions exist for exactly this reason.
- Accessible routes. A hump across a pedestrian path of travel is an obstruction. Keep them clear of accessible routes.
- Noise. Vehicles crossing humps generate noise, particularly trucks and particularly at night. On a site near residences that matters.
Body corporate sites
A common Sunshine Coast case. Traffic calming inside a residential or resort scheme is usually a body corporate decision, and installing humps on common property generally needs the committee's approval and sometimes a general meeting resolution.
Worth sorting the approval before the quote, because it is a frustrating way to spend two months. It is also worth checking the scheme's records to see whether anything was previously agreed about the road layout.